The invention relates to a heat-dissipating module, and in particular to a heat-dissipating module comprising a plurality of passages to provide airflow passing therethrough with uniform flow resistance.
Computer functions are integrally systematized on the same circuit or motherboard, decreasing space available in the housing thereof for convection and heat dissipation. Thus, forced convection by an electrical fan is employed to increase flow rate of air for dissipating heat generated therein. Broad narrowband noise and narrowband noise, however, increased as maximum static pressure and flow rate of airflow increase.
FIG. 1 is a perspective view of a conventional heat-dissipating unit G. The heat-dissipating unit G has a plurality of metallic fins U1, U2 arranged in parallel to form a plurality of channels U100 therebetween. FIG. 2A is a perspective view of the fin U1 of the dissipating unit G, and FIG. 2B is a sectional view of the fin U1 along line A-A of FIG. 2A. The U-shaped fin U1, same as the fin U2, has uniform thickness and a smooth surface on each side thereof.
As the heat-dissipating unit G is disposed next to or on a heat source such as a CPU (not shown), airflow S passes through the channels U100 directing heat on the fins U1, U2 to the exterior. Velocity distribution of airflow, as it is presented in a laminar flow, for example, is substantially the same as Poiseullie flow located near the side of the fin U1 to generate a corresponding designated noise spectrum. When a high-power fan is employed or the number of the fans is increased to elevate the volume and velocity of airflow, however, airflow with higher noise spectrum may be generated